This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose to investigate mechanisms of transepithelial ion transport in mosquito excretory epithelial cells and its control by a peptide hormone ion transport peptide. African malaria mosquito Anopheles gambiae inhabits in fresh water, requiring active absorption of ions through hindgut and anal papillae. The adult mosquito processes a large amount of the liquid food in a short period of time during and after the blood feeding. We hypothesize that ion transport peptide (ITP) is a major player in the control of mosquito osmoregulatory function as it is known for the locust. Basic biology of the ion transport peptide in the An. gambiae will be studied using various molecular and biochemical techniques. We will specifically ask questions when and where the ITP isoforms are expressed and secreted. The activities of the ITP isoforms on malpighian tubules and hindgut will be studied by measuring the rate of water transport, and by electrophysiological methods. Proposed research will provide the knowledge how the endocrine system controls transepithelial ion transport in mosquitoes. Understanding basic vector biology and physiology will provide rational approaches to develop environmentally benign insecticidal compounds that help to control vector-born diseases, improving human health.